1. Field of the Invention
The present invention relates to the improvement of a four-wheel vehicle.
2. Description of Background Art
A four-wheel vehicle according to the background art is known from, for example, Japanese Patent Laid-Open No. Hei 08-11770 (hereinafter “the JP '770 document). In the JP '770 document, an engine is set on one side with respect to a center line of the body extending in a longitudinal direction of the body. In addition, a rear cushion for suspending right and left rear wheels is set on the other side with respect to the center line of the body.
Referring to FIG. 1 of the JP '770, a four-wheel vehicle according to the background art will be described. The center of the engine 12 (the center of an engine cylinder 12a) is set off a center line L of the body by “a” on the left side and the rear cushion 24 is set off the center line L of the body by “b” on the right side. In addition, a gear box 25, a pipe 21a and a drive shaft (not shown) housed in the pipe 21a are arranged on the same side as the engine 12. The outside diameter of the pipe 21a is the largest portion of a rear arm 21.
The engine 12, the gear box 25, the pipe 21a and the drive shaft are arranged on the same side with respect to the center line L of the body. Since all of these elements are heavy, it is difficult to balance the side of the engine 12 and the side of the rear cushion 24 in weight based upon the center line L of the body.